Soft-Switching DC-DC Converter Is to shape the voltage or the current waveform by creating a...
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Transcript of Soft-Switching DC-DC Converter Is to shape the voltage or the current waveform by creating a...
Soft-Switching DC-DC Converter
Is to shape the voltage or the current waveform by creating a resonant condition to:
Force the voltage across the switching device to drop to zero before turning it ON Zero-Voltage Switching (ZVS)
Force the current through the switching device to drop to zero before turning it OFF Zero-Current Switching (ZCS)
Overview
• Many soft-switching dc-dc converter families were introduced in the open literature
• The objectives of these topologies are to develop high switching frequency converters with high power density and high efficiency
• This was accomplished by adding additional components to the power stage.
• Steady-state analysis tend to be time consuming.
• Provided little insight into the converter switching-cell operation.
Why Soft-Switching?
• Reduce switching losses especially at high switching frequencies
• Increase the power density, since the size and weight of the magnetic components is decreased by increasing the operating frequency
• Reduce the Electromagnetic Interference (EMI)
Conventional DC-DC Converters(Hard-Switching)
V in
+
-
V g
S
+
-vD
IF
iD
iswa
b
c
D C o
L o
R o
+
-
V o
IoI in +
-
V g
IF
a
+
vD
iD
c
S
isw
V F
-
bD
V inC o R o
+
-
V o
L o
+ -
V g
SIF
iswa c +-vD
iD b
D
V in C o R oL o
+
-
V o
I in
a
c
V in S
isw
D S
R o
+
-
V o
+
vD
iD
-
b
D C o
L oL i
+ -V g
C i
V in
S
iswa c
C o
L o
R o
+
-
V o
+
-vD
iD
b
DL i
C i
a
c
V in S
isw
b
L o
L i C i
R o
-
+
V oC o
+ vDiD -
D
Buck Boost
Buck-Boost Cuk
Zeta Sepic
Switching-Cell Sharing
All the Conventional DC-DC Converters shares the same
switching-cell
With different orientation of the cell in a specific converter
+
-
V g
+
-vD
IF
iD
a
b
c
D
S
isw
The Conventional DC-DC Switching-Cell
Switching-CellVg=Vab Vbc
-
+
+
-
IF
b
a c
Analyzed Soft-Switching Cells
(a)
(b) (c) (d)
(e) (f) (g)
+
-
V g
+
-vD
IF
iD
a
b
c
D
S
isw
+
-
V g
+
-vD
IFiLr
iD
a
b
c
L r
D
S
+ -vcr
D S
C r
vD
+
+
-
V g
IFiLr
iD
a
b
c
L rS
+
-vcr C r
-D
+
-
V g
S
+ -
+
+
-
-
V F
vcr
vD
IF
iLr
iD
a
b
c
C FL r
D S
D
C r
+
-
V g
IFiLra
b
c
SvD
+
-D
+
-
vcr C r LT
iT
D 1 L r +
-
V g
S
+
+
-
-
vcr
vD
IF
iDisw
a
b
c
L r
D S
D
C r
S 1
D 1
isw1
+
-vD1
+
-
V g
S
+
-vD
IF
iDisw
a
b
c
L r
D S1D
C r
S 1
D 1
isw1
+
-vD1
(a) Conventional Cell, (b) ZVS-QRC Cell, (c) ZCS-QRC Cell, (d) ZVS-QSW CV Cell, (e) ZCS-QSW CC Cell,(f) ZVT-PWM Cell, and (g) ZCT-PWM Cell
Zero-Voltage-Switching Quasi-Resonant
+
-
V g
+
-vD
IFiLr
iD
a
b
c
L r
D
S
+ -v cr
D S
C r
t2 t3t0 t0+T s
t
DS
iLr
V g
IF
t1
vCrV g+Z oIF
-IF
tc,on
ZVS-QRC Switching-Cell ZVS-QRC Cell Basic Switching-Waveforms
ZVS-QRC Family
+
-
V g
S
+
+
-
-
v cr
vD
IF
iD
a
b
cD S
D
C r
V in
L o
C o R o V o
IoI in
+
-
iL r
L r
+
-
V g
S
+
+
-
-
v cr
IFiLr
iD
a
bc
L r
D S
D
C r
R o
Io
V oC o
+
-
I inL i
V in
vD
+ -
V g
S
+
+
-
-
v cr
vD
iL r
a bcD S
D
C r
IF
iD
C o R o V o
Io
+
-
LV in
I in
L r
L r
S
+
+-
-
v cr
vD
iL r
iD
a b
c
L r
D S
D
C r
R o V oC o
+
-
I in L i
V in
L o IoV g
+ -
C i
S
+
+
-
-
v cr
vD
IF
iLr
iD
a
b
cL rD S
D
C r
V in
L o
C o R o V o
IoI in
+
-L i
C i
S
+
+
-
-
v cr
vDiLr iD
a
bc
L r
D S
D
C r
R o
Io
V oC o
+
-
I inL i
V in L o
C i
ZVS-QRC Buck ZVS-QRC Boost
ZVS-QRC Buck-Boost ZVS-QRC Cuk
ZVS-QRC Zeta ZVS-QRC Sepic
Zero-Current-Switching Quasi-Resonant
vD
+
+
-
V g
IFiLr
iD
a
b
c
L rS
+
-v cr C r
-D
t2 t3t0 t0+T s
t
DS
iLr
IF
t1
vCr
IF+V g/Z o
2V g
tCr-ptLr-p
ZCS-QRC Switching-Cell ZCS-QRC Cell Basic Switching-Waveforms
ZCS-QRC Family
+
-
V g
S
+
+-
-v cr vD
IF
iD
isw
a
b
c
DC rV in
L o
C o R o V o
IoI in
+
-
iLr
L r
+
-
V g
S
+
+
-
-
v cr
IFiLr
iD
isw
a
bc
L r
D
C r
R o
Io
V oC o
+
-
I inL i
V in
vD
+ -
V g
S
+
+
-
-
v cr
vD
iLrisw
a bc
DC r
IF
iD
C o R o V o
Io
+
-
LV in
I in
L r
L r
S
+
+ -
-v crvD
iL r
iD
isw
a b
c
L r
DC r R o V oC o
+
-
I in L i
V in
L o IoV g
+ -
C i
S
+
+ -
-v crvD
IF
iLr
iD
isw
a
b
cL r
DC rV in
L o
C o R o V o
IoI in
+
-L i
C i
S
+
+
-
-
v cr
vDIFiLr
iD
isw
a
bc
L r
D
C r
R o
Io
V oC o
+
-
I inL i
V in L o
C i
ZCS-QRC Buck ZCS-QRC Boost
ZCS-QRC Buck-Boost ZCS-QRC Cuk
ZCS-QRC Zeta ZCS-QRC Sepic